Generally described, turbo-machinery such as gas turbine engines and the like include a main gas flow path extending therethrough. Gas leakage, either out of the gas flow path or into the gas flow path, may lower overall efficiency, increase fuel costs, and possibly increase emission levels. Secondary flows may be used within the gas turbine engine to cool the various components heated via the gas flow path. Specifically, cooling air may be extracted from the later stages of the compressor for use in cooling the heated gas flow path components and for purging gaps in cavities between adjacent components. For example, conventional designs may incorporate metallic shims placed in slots between shroud segments so as to minimize any leakage flow therethrough. These gas flow path locations, however, may face very high heat fluxes and/or other operational parameters that may lead to heavy oxidation, creep, and resultant damage or failure.
As firing temperatures increase, the gas flow path temperatures may exceed the material limits of traditional seals so as to cause excessive leakage, loss of efficiency, and an overall reduced component life. There is thus a desire for improved turbine seals and related seal cooling techniques. Such improved turbine seals and techniques thus may accommodate the higher firing temperatures without loss of efficiency or lifetime.